1. Field of the Invention
The present invention relates to a ground structure for a tuner in an electronic apparatus.
2. Description of the Related Art
Conventionally, to reduce electro-magnetic interference caused by unintended radiation from an electronic apparatus which has a tuner or a high-frequency circuit, various ground structures have been developed. Such examples can be seen in the following documents.
JP-A-2005-295020 discloses a ground structure where a grounding leg of an electroconductive portion of a tuner facing a circuit board and an electroconductive portion of the circuit board are connected to form a first grounding. And an electroconductive portion of the tuner which does not face the circuit board and an electroconductive portion other than the circuit board are connected with a lead to form a second grounding.
JP-U-1988-147896 discloses a shield case for a tuner in which a ground plate having an elastic tongue is mounted on an engagement piece of a metal frame which supports a printed circuit board disposed in a metal frame body, and the elastic tongue touches a metal shield cover covering over the metal frame body.
JP-A-1996-107286 discloses a mounting structure for an electronic circuit apparatus where a ground conductive film, which is patterned on a bottom surface of a printed circuit board, touches a circuit-board contact portion of a lower shield box, and the inner surface of a side wall of an upper shield box touches a between-box contact portion of the lower shield box, thereby the upper and lower spaces of a high-frequency circuit block are shielded by both shield boxes.
When a circuit board having a tuner is mounted on a metal chassis, it is necessary to make a grounding between the tuner and the chassis. Conventionally, when fixing a tuner to a circuit board with a screw, one end of a metal ground plate was fitted into the tuner and fixed to the circuit board with the screw by fastening together, and the other end of the ground plate was made touch the chassis. In this structure, the ground plate had to have a length to reach from an edge of the circuit board to the screw-fixed portion, accordingly the ground plate became bulky and its shape was complicated.